Mechanical switching system



' June 26, 1923.

v 1,45 9,s59 W. T. POWELL MECHANICAL SWITCHING SYSTEM Filed June 12 1919 '4 Sheets-Sheet 1 INVENTOR WINFRED -r. POWELL.

ATTORNEY.

June 26, 1923. l,459,859

w. T. POWELL MECHANICAL SWITCHING SYSTEM Filed June 12 1919 4 Sheets-Sheet 2 4| 4 FIG.8

FIGS FI I I 34 35 e M Z5 3\ 32.

I it i so 0 I, 37 I7 20 I 3 6 48 i zl T INVENTOR WINFRED TI POWELL ATTORNEY June 26, 1923.

W. T. POWELL MECHANICAL SWITCHING SYSTEM .4 Sheets-Sheet 5 Filed June 12. 1919 INVENTOR WINFRED 1: POWELL.

BYA.

ATTORNEY June 26, 1923.

W. T. POWELL MECHANICAL SWITCHING SYSTEM Filed June 12, 1919 4 Sheets-Sheet 4 INVENTOR WINFRED T POWELk ATTORNEY Patented June 26, 1923.

stares 'WINFRED T. POWELL,OF ROCHESTER, NEW YORK, ASSIGNOR TO THE STROMBERG- CARLSON TELEPHONE MANUFACTURINGCOMPANY, OF ROCHESTER, NEW YORK,

A oonronn rro'n or NEW YORK.

MECHANICAL SWITCHING SYSTEM.

Application filed June 12, 1919. Serial No. 303,621.

T all whom it may concern.

Be it known that I, WrNrnnn T. POWELL, a citizen of the United States,residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Mechanical Switching Systems (Case 43), of whichthe following is a full, clear, concise, and exact description. a

The present invention relatesto telephone systems, and more particularly to telephone systems employing 'automaticswitches in establishing a connection between a calling and a called subscriber.

In former automatic telephone systems, especially those having direct impulse control,.it was necessary'to employ an arrangement of carefully adjusted relays which wereknown i-nthe art as fast land slow relays, the slow relays being," employed to measure time intervals. Since these relays must be manufactured with great care and since they'are not uniform in operation, it is proposed to 'p'rovide anautomatic telephone system in which carefully adjusted slow releasing r'elaysare eliminated.

, One feature of the invention is the provision of means by which an automatic switch maybe selectively and variably operated in response to impulses the number of which is the same irrespective of any one of anumber of positions towhichthe switch is adjusted. I

A further feature of the invention is the provision of circuits for automatic switches which will be selectively operated in "re sponse to the operation of an impulse transmitter or sender at a distant point whichis provided with resistances of various values.

lnthedrawingg Fig. 1 represents a front view of animpulse transmitter showing a rotatable finger-hold device and a stop member which-limits the forward adjustment of this finger-hold device.

FigaFZ-is aside view of the transmitter with the casing broken away onthe-line 29. of Fig. 1,'lookingin the direction of the arrows showing the arrangement of its interior mechanism.

Fig. 3 shows thefront and reverse sides of the A. commutator of thetransmitter tO- or sequence switch.

gether with the brushes that co-operate with the various segments of this commutator.

Fig. 4: represents the front and reverse sides of the B commutator of the transmitter together with variousbrushes for engaging conducting portions of this commutator.

Fig. 5 shows another side view ofthe interior mechanism of the impulse transmitter with the casingbrokenaway on the line55 of Fig. 1, looking in the direction of the arrows.

Fig. 6 represents a sectionalview'taken on the line 66 ofFig. 5, looking in the direction of the arrows,

Fig. 7 is a sectionalview of themeans -for rotating theA commutator ta-ken onthe line 7-7 of Fig. 5, and looking in thedirection ofthe arrows. Y

Figs. 8 and 9 represent different views of a clutch mechanism for operating *the B commutator.

Figs. 10 and 10 when taken together diagramatically represent a portion of a telephone system. At the left of Fig. 10 there are shown two dotted enclosures which diagrammatically indicate two senders or impulse transmitters,'one for the substation S, and the other for the substation 6 This sender maybe of the type disclosed in Figs. 1 to 9 inclusive. \Vithinthe dotted rectangles of 10 there are shown the circuits of two line switches, one line'switch being individual to the lineterminating at substation S and the other being individual to the line terminating at substation S", In Fig. 1(l the portion of theydrawing at the left of the dotted line shows-the brushes and contacts of asix pointsteering switch, In the center of the drawing a six-brush register, and at the extreme right of this figure there is shown a six-brush connector switch having fifty sets of terminals.

S'emZr or impulse transmitter.

In consideringthe structure and operation of the impulse transmitter of the present invention, it should be understood that two commutators referred to as A and B. are provided, each of which is arranged tocomplete different circuitclosures in each of the vari;

ous operating positions to which it is ad- 7 hold member reaches its normal position.

The commutator B is operated when the finger-hold member is returning to normal position and completes only one revolution for any number of impulses to be transmitted for any character.

In the drawings, 15 designates a cylindrical casing forthe operating mechanism of'the transmitter which is closed at oneof its ends and which carries a framework for supporting various elements of the transmit ter. A shaft 17 which is rotatably mounted in the frame and easing, has secured at one of its ends the finger-hold member '18, provided with a plurality of openings spaced an equal distance apart from each other about its periphery. There may be as many openings in this member as there are different combinations of impulses to be transmitted by the sender. A spring 19 is provided which is wound up when the fingerhold member is moved from normal position and operates to return this member and the shaft 17 to this position. A disc 20 secured to the shaft 17 is provided with a spring actuated pawl 21, which co-operates in the control of the B commutator in a manner to be described.

Near the intermediate portion of the shaft 17, there is secured the disc 22 to the upper surface ofwhich is secured a pawl 24 and a stop 25. A hollow cylindrical member, or

barrel 26, rotates on the upper portion of the shaft 17 as an axis. The lower portion of the barrel 26 is provided with a ratchet wheel 23' whichis arranged to be engaged by the pawl 24,- to cause the shaft 17 and the barrel 26 to rotate as a unit, as will be described. Directly above the ratchet wheel 23, and also secured to the barrel 26, is the A commutator'27. The structure of this A commutator is best shown in Fig. 3, from which it will be seenthat this commutator is formed of a circular disc of insulating material 28, to either side of which there are riveted conducting segments 29 and 30.

These segments are riveted together. by rivets of conducting material, so that they are electrically connected together. Three brushes 31, cooperate with a segment 30, and two brushes 32 co-operate with a conducting'segment29. A spring 33 is wound up when the barrel member 26 is rotated and operates to return this member to normal position indicated by the pin and stop "1 members 34. A second shaft 35 which is also rotatably mounted is provided with a spring 36, which tends to'restore the shaft is also secured to the lower end of the shaft,

35 and is provided with a notch, so positionedthat it will be engaged by-thepawl 21. The shaft 39 previously mentioned is rotatably mounted in the frame on an axis parallel to the axis of shafts 35 and 17. The

upper end of the shaft 39' is provided with a clutch member 40 co-operating with a sec- 0nd clutch member 41 mounted onthe lower end of the shaft 42. These clutch members 40 and 41 co-operate to cause shafts 39 and 42 to rotate together on the rotation of the shaft 39. The shaft 42 near its intermediate portion carries the B commutator 43, which is s'tru'ctually similar to the A commutator, except that itsconducting segments are differently arranged. The B commutator 43 has two sets of brushes 44 and 45, one set engaging each surface of the Bcommutator.

The operation of the impulse transmitter is substantially as follows: The subscriber places his finger in any oneof the openings of the finger-hold member 18 and rotates it in the direction of the arrow until his finger engages the stop 46. This operation winds up the spring 19 and rotates the disc 20 with its pawl 21' until this pawl engagesthe notch in disc 59. The disc 22 is also rotated with the shaft17 in the direction of the arrow, causing the pawl 47 mounted on the frame to disengage the stop 25, and permits the pawl 24 to engage the ratchet wheel 23, so that in the further rotation of the finger-hold member 18 andthe shaft 17, the barrel 26 will be rotated therewith. Nhenthe barrel 26 is thus rotated, the A commutator 27 is rotated to cause it to take a desired setting with respect to the brushes 31 and 32, and the spring 33 is wound up to cause the barrel 26 and the members carried thereby to be rotated to normal when the pawls 24 and 47 disengage the shaft 23. This operation of restoring the barrel 26' to normal' occurs when the finger-hold member 18 has almost reached its normal position, when pawl 24 has engaged arm 50 and pawl 47 has ongaged stop 25.

When the shaft 17 is being returned unneaagase various circuits through its sets of brushes 4:4: and 45.

In the further operation of restoring the finger-hold member 18 to normal position, the pawl 21 is moved downward until its projection engagesthe stop 49 carried by the frame, which raises the pawl 21 out of engagement with the notch ot' the disc 59 and permitsthe shaft tobe rotated to normal position determined bystop-GO (Fig. 6) under the control of its spring 36. While the shaft- 35 is being restored to normal, the teeth of the cam 37 carried by it reengage the star wheel 38, which rotates the shaft 39 to normal position. The clutch members 410 and ell however do not engage each other at this time, so that shaft 12 is not rotated.

Just before the finger-hold member 18 has reached normal position, the pawl 43? carried by anarm of the frame is disengaged from the ratchet wheel23 by stop 25 and the barrel '26 is permittedfto rotate independently of the shaft 17. lVhen this takes place the barrel 26 is rotated under the control of the spring 33, until the pin and stop members 3 liare in engagement. The apparatus is now in condition to transmit the next series of impulses.

Sender 01" impulse tymzsm-z'tlcr circuits.

The sender or impulse transmitter in its normalposition is connected in series with the two conductors of a telephone line, as follows: conductor 100, contact 101 of the B commutator, contacts 102 and 103013 the A commutator. through the transmitter, through. the switchhook and contact 104-,to the conductor 105 ot the telephoneline. The small numerals adjacent to the various contacts, such as contacts 101, 1.02 and. 103 in dicate in which positions of the commutator of the sender or impulse transmitter these contacts are closed. By a study oi the circuits of this sendertogether with the structure, it will be seen that the saininumber of impulses is transmitted by the B commutator for any number set up on the sender, but that certain combinations of impulses dift'er from other combinations in the intensity of the several impulses of. which it is composed. n

In the present description reference will be made to signaling circuit, this circuit may include two sides of a subscribers telephone line, such as conductors'100 and 105 and two sides of the trunlrline, such as 117; and 118 that has been connected tothis tele phone lineby means of an automatic switch. This signaling circuit includes in series a release relay 200 10 which is maintained energized from the initiation. of the connection until the time'of disconnection, and two other relays202 and 203 (Fig.1?) are also include-d in series in this signaling circuit and are responsive to impulses of a seen that as soon as the receiver switchhook is raised, the three relays 200, 202 and 203 will be energized. Then after the seting of the A commutator, either orboth of the relays 202 and203 will be deene'rgized, then, inthe operation of the B commutator all of the relays will be energized followed by a deenergization of the relay 202, or relay 203. This alternate energiziation and deenergization or these relaystalres place through the five operating positions of the B commutator. Although for purposes of this disclosure the resistances 121 and have been given values of 1000 ohms each,

it will be understoodthat there may be a wide variation of the values of these resistances without departing from thespiritof the invention.

' Impulse chart.

A commutator. B commutator positions.

Dial Dial pulled forward. 1 2 i 3 4 i i 5 I o. 3 Open. close. open. close. open close.

Ohms Oh'ms. Ohms. Ohms. Ohms. Ohms. 1 1000 1000 0 1000 0 2 1000. 0 1000 y 0 2000 0 3 1000 0 2000 0 1000 i 0 4 1000 A 1 0 2000 0 2000 0 5 1000 then 2000. 0 1000 0 1000 0 6 1000 then 2000 0 1000 0 2000 0 7 1000 then 2000 0 2000 0 1000 0 8 1000 then 2000 0 2000 0 2000 0 9 1000 then 2000 then 1000 0 1000 0 1000 0 i 0 i i 1000 then 2000 then 1000 y 0 1000 0 2000 0 R 1000 then 2000 then 1000 0 2000 0 1000 0 T 1000 then 2000 then 1000 0 2000 0 2000 0 From this chart it will be seen that when the finger-hold member is set in any oi? its positions from 1to 1 inclusive, 1000 ohms are included in the signaling circuit by the ion ward adjustment of the A commutator. When this member is adjustedto positions 5 to 8 inclusive, 1000 ohms resistance and then 20000111119, resistance are included in the mentioned signaling circuit, and when this member is. set in any of the positions 9, 0, R or T, 1000 ohms is first included in the signaling circuit followed by the inolusion or'aoeo ohms resistance, and then 1000 ohms resistance "on theforward adjustment of the A commutator.

It will also be seen that in positionsi,

ing'circuit,'while in positions 2 and t of the B commutator 1000 or'2000 ohms resistance is included in this circuit inaccordance with the number set up by the finger-holdmems ber.. v

Gil/art showing setting of registcr.

, Steering switcln Dial Reg- 1 N0. ister.

2. 2 3 3 4. 4 5. to 5 5 6. N to 5 a-O 6 7. N I to 5 5-6 fi7 7 8. N to 5 5-6 6-7 7-8 8 0 N-Q v 9-10 10 R -N-9 9-10 10-11 11 T N-9 3-10 10-11 11-12 12 This-chart showing the setting of the register, indicates that the re ister assumes a position in accordance with the adjustment of the finger-hold member of the dial switch, and also shows in which positions of the steering switch the register is advanced to its designated setting.

Switch structure,

The switches used inthis system; are of the unidirectional rotary type, that is, they have a plurality of sets of contacts arranged steering switches and registers are advanced to their normal posit-ion when not engaged, but the line switches and connectors have no normal positions but remain in engagement with the contacts last used.

The line switch differs slightly in form from other rotary line switches of the art, in that incoming and outgoing trunks terminute in. its contacts, the outgoing trunks being-used to extend the calling line toa numerical switch or connector switch, and,

the incoming trunks being employed to extendthecalled line to its respective set of contacts at the connector switch usedin extending the call to this line.

Detailed description of system.

It is believed the invention will best be understood by describing the method of establishing a connection betweena calling substation indicated at S, and a called substation indicated at S which it may be assumed, is designated number 32. When the calling subscriber at, 6 removes his receiver from its switchhook, a line relay LR,

individual to the calling line, is operated over a circuit extending from grounded battery, winding of this relay, upper inner back contact and armature of the cutoff relay CO, conductor 100, normal contact 101 ofthe B commutator, normal contacts 102 and 103, the transmitter through the switchhook and contact 104, primary winding of the induction coil, conductor 105 to ground at the uppermost armature and back contact of cut-off relay CO. v v i I The line relay LR is energized in this circuit, and at its left hand armature and front contact closes a circuit from grounded battery, resistance, back cont-act, armature, and winding of the motor magnet MM'of the line switch, left hand armature and front contact of the line relay, uppermost armature and back contact of. the cut-off relay CO, to ground. Under'the control of this circuit, the motor magnet h/IM is energized, causing the five brushes of the line switch to be advanced step-by-step until an idle trunk is found. At the right hand front contact and armature of the line relay LR, a break point in the test circuit is closed to extend this test circuit from grounded battery, resistance, back contact and armature of the motor magnet MM,- continuity spring and contact, and lower windingv of the cutoff relay CO, conductor 106, right hand armature and front contact of the line relay LB,

test brush 107, over a test terminal corre spending to 108, test conductor 109, continuity contact and spring of the rela.y"200, conductor 201, normal contact and brush 4 of the steering switch, to ground. The

motor magnet MM of the calling line switch is shunted to stop the switch while the cutoff relay is energized by this circuit, the cutoff relay attracting its armature to complete a locking circuit for itself from grounded battery, back contact and armature of the motor magnet MM, continuity spring and inner lower armature and'uppe1;- winding of the cut-off relay, which is high resistance, brush 110,. terminal 111, conductor-112, to ground at normal contact and brush 4 of the steering switch. The cut-off relay is locked energized in this circuit and at its upper armatures interrupts the energizing circuit of the line relay LR, and extends calling line conductors and through the line brushes 113 and 114, to the selected trunk terminals."

hen an idle trunk has beenseized in the manner just described, a circuit as closed from grounded battery, winding of the relay 200, trunk conductor 118, trunk terminal 116, line brush 11 1-, through the calling subcribers substation circuits, line brush 113, trunk terminal 115, trunk conductor 117, windings of the relays 202 and 203, to ground. Since this circuit is of relatively low resistance, relays 200, 202 and 203 are energized, and the relay! 20.0 attracts its armatures to apply groundto theholding conductor 201, which maintains the cut-oft relay CO energized. When the relays 202 and 203 were energized, they completed a circuit for the motor magnet 204; of the steering switch, from groundedbattery, winding back contactand armature of this motor magnet, brush 1 of the steering switch in its normal position, conductor205, innermost front contact and armature oi the relay 202, front contact and armature of the relay 203, to ground.

Under the control of the circuit just described, the motor magnet 20% advances the steering switch into its first position and the apparatus is now in conditionto receive the directive impulses from the sub-- scribers dial switch. The subscriber. now operates his dial switch in accordance with the first digit of the desired number. Since it was assumed that the wanted number is 32, the subscriber then sets his dial to trans mit impulses correspondingto thenumber 3. Under this assumption the commutator A will first be operated to include the 1000 ohms resistance 122m thesignaling circuit while the finger-hold member being rotated forward It will be remembered that the A commutator remains in the position to which it has been rotated while the finger-hold member is returning, but releasesuwhen the finger-hold member gets to a point corresponding to position 5 on the ,B commutator. The B commutator, however, moves backward with the finger-hold member and makes one complete revolution for any number to which theiinger-hold member has been adjusted. Therefore. while the Acornmutator remains in position 3, the B commutator, in the present case, in makinga complete rotation to normal position, first short-circuits the resistances 121 and 122 and then includes both of the 1000'.ohm resistances 121 and 122 in the signaling circuit while moving through position 2., While moving through position 3, thebrush 120 of the commutator B will short-circuit both of the resistances mentioned. In position 41-, the resistance 122 is included inthe signaling circuit, while in position 5 of the B commutator both of the mentioned resistances are short-circuited, and when the B commutator reaches normal position these resistances are shunted by the transmitter.

Let us first consider the effect of the impulses transmitted by the setting of the A commutator. As soon as the resistance 122 is included in the signaling circuit, marginal,

net 204 to grounded battery'. This circuit operates to move the steering switch to position 2. As soon as the steering switch has moved into position 2, a circuit is closed from ground at brush 4; of thisswitch, conductor 208, brush or the register in its nor-. mal position, back contact and armature and winding of the motor magnet 207, to grounded battery, to movethe register into position 1.

In the further operation of the sender, the

Acommutator remains in position 3 and the- B commutator leaves i'ts'normal position and advancesto position 1, whereupon the resistances 121 and 122 are short circuited from the signaling circuit and the relay 203 becomes energized. The steering switch is now advanced to position 3 by. a circuit extending from grounded battery, winding of the motor magnet 204, brush 1 of the steering switch in its second position, conductor 205, front contactsand armatures of relays 202 and 203 to ground. lVhen the B commutator advances to position 2, resistances 121 and 122 will be included in the signaling circuit which will cause the relays 202 and 203 to retract their armatures. This closes circuit from ground,armature and back contact of the relay 203, conductor 206, brush 1 of the steering switch in its third position, armature and back contact and winding of, its] motor magnet 20 1, to grounded battery to move the steeringswitch into position at. Withthe steering switchin posit-ion 4, a circuit is closed for moving the register into position 2, which is completed from grounded battery, winding, armature and back contact of the motor magnet 207, brush 1 of the register, conductor 209, brush 6 of thesteering switch, conductor 210, armatures and back contacts of relays 202 and 203 to ground.

As the B commutator advances to position 3, the resistances 121 and 122 are again shunted from the signaling circuit which allows relays 202 and 203 to energize. The steering switch is now advanced to position 5 .over a circuit from grounded battery, winding of its motor magnet 20 1, its back contact and armature, brush 1 in its fourth position, conductor 205, front contacts and armatures of relays 202 and 203 to ground. The register is now moved to position 3 over its brush 1 and brush 3 of the steering switch to ground over conductor 205. Then the B commutator advances into position at, the resistance 122 is again included in the, signaling circuit, which causesthe relay 203 to release and advance the steering switch to positime 6. The B commutator continues to move to position 5 wherein the mentioned resistancesare short circuited and the relay 203 energized to. close a circuit for advancing the steering switchfto position 7. When the B commutator reaches position 5,-the commugrounded battery,'its lower winding, con

ductor 221, brush 4 of the steering switch in position 7, to ground. The starting relay 212 attracts its armatures, and at its upper armature and front contact closes a locking circuit fromground, through its upper winding, resistance 213, to grounded battery. At the lower-most armature and front contact an operating circuit for theconnector switch is closedffrom ground, winding of the motor magnet 214, conductor 215, lower-most armature and front contact of relay 212, lower-most armature and back contact of the relay 216, resistance to grounded battery.

Under the control of this operating circuit, the motor magnet 214 of the connector switch continues to advance this switch until its brush 2 engages the contact to which conductor 217 leading to point 3 on the register is connected, whereupon the motor magnet 214 is shunted by a circuit closed from ground, upper armature and front contact of relay 212, upper winding of the stopping relay 216, brush 5 of the register in its third position, conductor 217, brush 2 of the connector, conductor 215, lower-most armature and front contact of relay 212, lower-most v armature and back contact of relay 216, re

sistance to grounded battery. The stopping relay 216 is energized in this circuit and since its inner-most front contact is closed before its lower-most contact is opened, the stopping relay completes a locking circuit for itself from grounded battery, its lower winding, its inner-most front contact and armature, conductor 218, continuity contact and spring of relay 219, to ground. The connector switch is thus set in operative relation to the group of linesthrough which the wanted line may be reached.

As soon as the relays 212 and 216 are energized, a circuit is closed for advancing the steering switch from position 7 to position 8. This circuit extends from grounded battery, winding of the motor magnet 204, its back contact and armature, brush 1 of-the steer-' ing switch in its seventh position, conductor 220,'inner=most armature and front contact of relay 212, middle armature and front contact of relay 216, conductor 221, brush 4 of the steering switchin its seventh position, to ground. I

l/Vhen the steering switch is in its eighth position, an operating circuit is closed for the motor magnet of the register to move this register from the position in which it was resting, which was position 3, into position naling circuit when the A commutator is positioned, which causes relay 203 to retract its armature and thus close a circuit from. ground, armature and back contact of the relay 203, conductor 206, brush 1 of the steering switch in its eighth position, armature, back contact and winding of the motor magnet 204, to grounded battery. Under the control of this circuit, the steering switch is advanced to position 9, whereupon a circuit is closed from ground, brush 4 of the steering switch, conductor 208, brush 2 of the register in its thirteenth position, back contact, armature and winding of the motor magnet 207, to grounded'battery. Under the control of this circuit the motor magnet advances the brushes of the register into their fourteenth position.

As the B commutator of the sender is rotating through position 1, the relay 203 will again be energized, whereupon a circuit is closed over conductor 205 to advance the steering switch from position 9 into position 10. In position 10, however, of the steering switch, the register remains inactive. While the B commutator of the sender is rotating through position .2, the resistance 122 is included in the signaling circuit, causing relay 203 to'retract its armature. This closes a circuit over conductor 206, to advance the steering switch from position 10 to position 11.

In the third position of the B commutator,

the resistances are short circuited from the signaling circuit, and the relay 203 energizes to close a circuit over conductor 205 to move the steering switch out of position 11 and into position 12. As the B commutator is moved to position 4 resistances 121 and 122 are both included in the signaling circuit, causing both of these relays to retract their armatures. At the armature and back contact of the relay 203, a circuit is closed for the motor magnet 204 of the steering switch, to move this switch from position 12 into position 13. Thereupon the register is advanced from position 14 to position 15, over an operating circuit from grounded battery, J

motor magnet 207, brush 1 of the register, conductor 209, brush 6 of the steering switch, conductor 210, armatures and back contacts of relays 202 and 203, to ground, When the sender reaches normal position, both of the i upper armature and back contact of relay insejsse 1 v resistances areshunted fromthe signaling circuits and relays202 and 203 are both energized. This closes a circuit over conductor 205 for advancing the steering switch from position 13 to position let. At this time the starting relay 212 which has remained energized during this interval is short circuited by ground at brush e1 ofthe steeringswitch. As soon as the starting relay 212 deenergizes, an operating circuit for the motor magnet 214 of the connector is closed from ground, winding, armature and back contact of this motor magnet, conductor 215, lower-most armature and back contact of relay 212, lower-most front contact and armature of relay 216, resistance, to grounded battery. Under the control of this circuit, the motor magnet advances the connector switch over the terminals of the. previously selected group and continues this movement until its brush 1 engages a terminal corre sponding to the wanted line 32. Then this terminal is reached, the. relay 219 is ener gized over a circuit completed from ground,

212, conductor 225, upper winding of relay 219, brush 4; oi? the register in its fifteenth position, conductor 226, brush 1 of the connector, conductors 227 and 215, lower-most armature and back contact 01 relay 212, lower-most front contact and armature of relay 219, to grounded battery.

, It will be noted that the motor magnet 214i is shunted by the circuit just described. The relay 219 is energized in this circuit and closes a locking circuit for itself from grounded battery, resistance, conductor 228, lower winding of relay 219, lower armature and continuity spring of this relay, to ground. When this lockingcircuit for this relay 219 is completed, the locking circuit for the relay. 216 is interrupted at the continuity spring of relay 219. Also when the relay 219 was energized, it closed a circuit from ground, its inner upper armature, conductor 229, brush 1 of the steering switch in its "fourteenth position, armature, back contact and winding otthe motor magnet 204: of the steering switch, to grounded battery. This circuit operates to move the steering switch from position 14 into position 15. In position 15, the relay 219 is short circuited by ground over brush i of the steering switch, conductor 230, and the resistance to grounded battery. As soon as relay 219 deenergizes, it closes a circuit from ground, its inner upper armature and back contact, conductor 231, brush 1 of the steering switch inposition 15, armature, back contactand winding of the motormag-net 20 1to ground ed battery to move the steering switch into its sixteenth position. In position 16, an operating circuit is closed for the motor magnet of the register which moves itinto position twenty-six. This circuit is completed from grounded-battery, winding, 4

mature and back contact of the motor mags net 207, conductor 222, brush 3 in any of its positions from 14 to 25, conductor 223, brush 4: of the steering switch, to ground. As soon as the register reaches position 26, it closes a circuit for moving the steering switch out of position 16 intoposition 17, which circuit is closed from grounded battery, winding, back contact and armature of the motor magnet 204, brush 1 in its sixteenth position, conductor 232, brush '3 of the register in its twenty-sixthposition, conductor 223, brush 4: of the steering switch, to ground. In position 17, the relay is energized over brush 4 of thesteering switch and attracts its ar matures. This closes a circuit from ground, inner lower armature and front contact of relay 233, conductor 234:, through both windings in series or' test relay 235, back contact and armature of relay 236, brush i of the connector, conductor 237, lower-most armature and back contact of the cut-off relay CO, winding, back contact and armature of the motor magnet MM, resistance, to grounded battery.

Since the called line is toundidle, the relay 235 is energized and short circuits its high resistance winding and causes the line switch individual to the callingline to advance until it reaches the point on its terminal bank corresponding to the connector used in calling it. When this point is reached, the cut-off relay CO individual to the called line willbe operated and the motor magnet MM will be shunted by a circuit traceable from grounded battery, resistance, back contact and armature of the motor magnet MM, continuity spring contact and lower winding f the cut-off relay CO, right hand armature and back contact or the line relay LR, line switch, brush 130, terminal 131, conductor 132, brush of the connector, conductor 235, brush 1 of the register in its twenty-sixth position, upper winding of relay 219, conductor 225, upper back contact and armature of relay 212, to, ground. The, called line switch is stopped, by this shunt circuit and the cut of relay holds open the operating circuit of the motor magnet MM and completes a circuit for itself through its upper winding, conductor 133, winding of the relay 236, conductor 238, inner lower front contact and armature of relay 233, to ground. Relay 236 when energized interrupts the energizing circuit or the relay 235.

The called subscriber is now signaled by signaling current transmitted from grounded. battery, resistance, generator: 239, interrupter brush 2 1-0, lamp 2%1, slow-releasing trip relay 2 12, brush 6 or" the register in its twenty-sixth position, conductor 243, brush 6 ofthe connector, conductor 24 1, through the called subscribers line and substation circuits, conductor 132, brush 5 of the conof position 26 and into position 27.

I an

v called line is busy.

} Talking battery is supplied to the calling line through the relays 200 and 202, the relay 203 being short-circuited by the relay 233 to insure that the calling line will be properly balanced. Talking battery for the called party is suppiled through the windings f the impedance coil. I

Let it be assumed that the wanted line was busy. Under this condition the test relay 285 will be energized in circuit closed from grounded battery, resistance 251, armature and back contact of relay 236, both windings of relay 235 in series, conductor an, inner lower armature and front contact of relay 233, to ground. It wilibe unde stood that the resistance coil 251 is of relatively high resistance as compared with the resistance of the motor magnet of the line switch.

Since the called line is assumed to be busy,

its cut-ofi relay is energized and the only energizing path. for the relay 235 is through,

the high resistance path just described. The high resistance COll 251 will not permit the relay 285 to be maintalned energized through its low resistance winding, and this relay will therefore produce a tone in the call ng partys receiver indicating that the W hen the calling party desires to disestablish the connection. either because the conversationis completed or'because the called line is busy, he places his receiver on its switchhook and opens the line circuit which is included in the signaling circuit pre viously mentioned... The relay 200 which is energized as soon as the call is initiated and remained energized during the establishment of the call. and during the conversation, deenergizes. As soon as the relay200 deenergizes, it closes a circuit from ground at its upperarmature and back contact, conductor 252, brush 2 of the steering switch in any 'of its positions, from 1 to 18, armature,

back contact and winding of the motor magnet 204, to grounded battery to advance thesteering switch in position 19. lVith the steering switch thus positioned, the register is restored to normal position over a circuit closed from grounded battery, winding, armature andback contact of the motor magnet 207, brush 1 of the register, brush 2 of the steering switch, conductor 25,2,back contact and armature o1"- relay 200,,to ground. As soon as the register has been restored to normal position, the steering switch is alsomoved to its normalposition by a circuit closed from grounded battery, winding, back contact and armature of motor magnet 20 i, its brush 1, conductor 253,brush 3 oi the register, conductor 23, brush 4; of the steering switch in its. nineteenth position, to ground. The steering-switch and register used in establishing the connectionare restored to normal in the manner described.

The calling and called line switches and connector, however, have no normal position, but remain in the position to which they were adjusted..duringthe establishment of the call. As soon as. the steering switch lei't position17, the circuit through the brushes 3 and 5 of the connector was opened, and when the register leitt position 27, the brush 6 was opened. as soon as ground was re- .moved from the connector brush 3 of the called line, relay CO' was released, and when the relay 200 retracted its armatures it removed theeround potential from conductor- 112, which permitsthe cut-off relay of the calling line switclrto release. The apparatus is now in condition to establish another connection. 7 I i I It will be understood that the present dis closure is'merely typical of applicants invention, and-that there may be many changes and variations'in the'same within the scope from the inventive idea.

lVhat I claim is: l

1. In a telephone system, a telephone line, an impulse transmitting device for sending combinations of impulses differing only in character over two sides of said telephone line in series, animpulse receiving device variably operated in response to saidimpulse transmitting device, and an automatic switch which assumes a position in accordance with the adjustment of said impulse receiving device. i

In a telephone system, a telephoneline, an impulse transmitter. which transmits the same number of impulses for a plurality of different designations over two sides of said telephone line, an impulse receiving device variably operated in response to said impulse transmitter, and an automatic: switch which assumes a position in accordance with the adjustment of said impulse receiving device. 1

8. In a telephone system, a telephone line, an impulse transmitter for transmitting combinations of impulses differing only in the intensity over two sides of said teleof the appended claims without departing phone line in series, an impulse receiving deance with the adjustment of said impulse receiving device. i I i In a telephone system, a telephone line, an impulse transmitter for sending the same number of impulses, said impulses for a plurality of different designations over two sides of said telephone line inseries consist ing of electric currents of diilerent intensities, an impulse receiving device variably operated in response to said impulse trans mitter, and an automatic switch which assumes a position in accordance with the adjustment of said impulse receivingdevice.

In a telephone system, a telephone line,l a link circuit terminating in an auton'iatic switch, means for interconnecting said line and said linkcircuit, an impulse transmit-- ter connected to said telephone line, said impulse transmitter being arranged di'tl'erent combinations of lllllllllSQSOjlf di ilerent intensities, certain combinations. being: always composed ot the same number oi lidpulses, and an impu se receiving device variably responsive to said impulse transmitter and associated with said link circuit, said automatic switch operating in accordance with the setting of said. impulse rcceivi n device to assume a position predetermined by said impulse transmitter.

(3. In a telephone system, a telephone line, a link circuit terminating in an automatic switch, means -For interconnecting said line and said link circuit, an impulse transmitter connected to said telephone line, said impulse transmitter being arranged to send coml'iinations of impulses (littering in intensity, and an impulse receiving device varial'ily responsive to said impulse transmitter and associated with said link circuit, said automatic switch operating .in accordance with the setting of said impulse receiving device to assume a position predetermined by said impulse transmitter.

7. In a telephone system, a telephone line,

a link circuit terminating;- in an automatic switch, means for interconnecting said line with said link circuit, an impulse t 'ansmitter connected to said telephone line, said impulse transmitter being arranged to send combinations of impulses, certain combinations being composed of the same number of impulses, but varying in intensity, and an impulse receiving device variably re sponsive to said impulse transmitter and associated with said link circuit, said automatic switch operating in accordance with the setting of said impulse receiving device to assume a position predetern'iined by said impulse transmitter.

8. In a telephone system, an automatic switch, a signaling circuit associated therewith, a sender connected to said circuit and arranged to send impulses thereover, a release relay and impulse relays serially included in said. circuit and arranged to be controlled thereover, each ofsaid in'ipulsc relays being responsive to certain impulses from said sender to directively control the setting of said automatic switch, said release relay being unresponsive to impulses from said sender andoperating to control the release olf said automatic switch. i

9; in a telephone system, a telephone line, a plurality of trunk lines each terminating in automatic switches, means tor-intercom necting said telephone line with any of said trunk lines, a sender connected to said telephone line and operating to transmit impulses over said. telephone line. and the corn nected trunk line, said sender being manic ally adjusted to indicate, a desired setting of said automatic switch, means at said sender operable after its manual adjustment to transmit combinations oi? impulses ig in intensity, and means associated with said automatic switch tor receiving said impulses to control the setting of said automatic switch.

10. In a telephone system, an incoming; line, a plurality of outgoing lines, an automatic switch to interconnecting said,in

coming line with any of said outgoing lines, a control-circuit for said automatic switch including a portion of the two sides in series of said; incoming line, and an impulse trans mittcr having a plurality of resistances arranged to be variably included in said con trol circuitto govern the setting of said automatic switch. j

11. In a telephone system, an incoming line, a plurality o t outgoing lines, an auto matic switch for interconnecting said incoming" line with any of said outgoing lines, acontrol circuit for said automatic switch including a portion of said incoming line,

and an impulse tItiIlSllilttGr having a plu rality of resistances of substantially equal value arranged to be variably included in said control circuit to govern the setting of said automatic switch.

12. In a telephonesystem, an incoming line, a plurality of outgoing lines, an automatic switch for interconnecting said in coming line with any of said outgoing lines, a control circuit for said automatic switch including a portion of two sides of said in coming line, and an impulse transmitter having a plurality of resistances arranged to be variably included and eliminated from said control circuit in proper sequence to selectively control said automatic switch.

13. In a telephone system, a plurality of telephone lines, trunk lines terminating in numerical switches, a line switch and an impulse transmitter individual to each telephone line for transmitting impulses of variable intensities, means including a line switch for extending a line to one of said numerical switches, impulse receiving means associated with said numerical switch and responsive to said lll'lPLllSE transmitter of the mentioned line for deslgnatmg the wanted line, and means tocause said numerical switch to hunt for the designated line.

' a line switch individual to each line, said '14. In a telephone system, a plurality of telephone lines, trunk lines terminating in numerical switches, a line switch and an iinpulse transmitter individual to each telephone line for transmitting impulses of different intensities, means including aline switch for extendinga line to one of said numerical switches, impulse receiving means associated with said numerical switch and responsive to the'impulse sender-of the men tioned line for characterizing the wanted lineatsaid numericalswitch' with a selectable cond1t1on, and means for causing SfllCl numerical switch to hunt for said wanted line. l

- 15. In a telephone system,an incoming line, aplurality or". trunks terminating in numerical switches, means for interconnectmg saidlncoming line with any of said trunks, outgoing lines terminating 1n said numerical switches, an impulse transmitter associated with said incoming line and arranged to transm t impulses of different 1ntensities thereover, means associated with a selected trunk and operated in response to said impulse transmltter for characterizing a wanted outgoing line at a selected'numerical switch with a selectable condition, and means for causing this numerical switch to hunt for the wanted line.

' 16. Ina telephone system, a plurality of telephone lines, an impulse transmitter and impulse transmitter being arranged to transmit impulses of different intensities, means for extending a telephone line includ ingits line switch and a numerical switch, means associated with said numerical switch responsive to said impulsettransmitter for charaeterzing a wanted telephone line by a selectable condition, and a mechanism for causing said numerical switch to hunt'for the' line so characterized.

line so characterized-rand*means operative when the wanted line is found by said numerical switch, to cause the line switch individual to the wanted line tohunt forthe terminals of said numerical switch that are individual to thiswanted line.

18. Ina telephone system, an incoming line a plurality of outgoing lines terminating in numerical switches, means for interconnecting said incoming line'with any of said outgoing lines, an impulse transmitter for said incoming line, a metallic signaling circuit for the numerical switch that has been connected to said incoming line, means associated with the selected numerical switch and variably responsive to an invariable number of impulses transmitted. over said signaling circuit from said impulse trans mitter to selectably control the setting of said numerical switch. 7 a

In witness whereof, I hereunto subscribe my name this 10th day of June, A. D; 1919.v

WINFRED T. POWELL. 

